Heat exchanger

ABSTRACT

A heat exchanger with separate paths of flow for two media, comprising preferably circular metal discs arranged in succession in a shell. The paths of flow are through three groups of radially discrete openings provided in each disc, said paths being sealed off from one another by rings positioned between adjacent discs. Means are provided to communicate the group of central openings with the inlet and the outlet for the first medium, to form the path of flow for the first medium, and means are likewise provided to interconnect the radially inner and outer groups of openings and also to connect them individually to the inlet and the outlet for the second medium, to form the path of flow for the second medium.

United States Patent [1 1 Ostbo HEAT EXCHANGER [76] Inventor: Karl Robert Ambjorn Ostbo,

Storgatan 2, 8-510 80, Tranemo, Sweden [22} Filed: Sept. 7, 1972 [21] Appl. No: 287,041

[30} Foreign Application Priority Data Feb. 11, 1975 Primary ExaminerCharles J. Myhre Assistant Examiner-The0phil W. Streule, Jr. Attorney, Agent, or Firm-Newton, Hopkins & Ormsby [57] ABSTRACT A heat exchanger with separate paths of flow for two media, comprising preferably circular metal discs arranged in succession in a shell. The paths of flow are through three groups of radially discrete openings provided in each disc, said paths being sealed off from one another by rings positioned between adjacent discs. Means are provided to communicate the group of central openings with the inlet and the outlet for the first medium, to form the path of flow for the first medium, and means are likewise provided to interconnect the radially inner and outer groups of openings and also to connect them individually to the inlet and the outlet for the second medium, to form the path of flow for the second medium.

3 Claims, 4 Drawing Figures PATENTED FEB I I I975 SHEEI 10F 3 PATENTEB FEB] H575 SHEET 2 OF 3 HEAT EXCHANGER BACKGROUND OF THE INVENTION The present invention relates to heat exchangers of the kind comprising a unit of preferably circular metal discs enclosed in a shell in the form of a cylinder jacket closed by two end walls, each one of said discs being provided with a number of openings so disposed and separated into groups by means of medium-separating sealing rings arranged in the space between neighbouring discs, that separate paths for two different media are formed.

SUMMARY OF THE INVENTION Characteristic of the invention is that the openings are arranged in at least three, radially discrete circular groups, and that an annular junction channel is arranged externally of each outer disc of the unit in the area of the radially middle group or groups of openings and connected with the inlet and the outlet, respectively, for the first medium, which outlet and inlet communicate with the shell end walls, whereas the outer group and the inner group of openings communicate with each other externally of each outer disc of the unit and are individually connected with the outlet and the inlet, respectively, for the second medium.

The invention provides a heat exchanger creating an extremely good heat transfer efficiency despite its comparatively small dimensions.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics of the invention will become apparent upon reading of the following detailed description with reference to the attached drawings, wherein FIG. 1 illustrates a longitudinal section through a heat exchanger in accordance with the invention, and

FIG. 2 illustrates, on a somewhat larger scale, a plan view of one of the metal discs of the heat exchanger.

FIG. 3 illustrates a longitudinal section through a heat exchanger of a somewhat different embodiment of the invention, and

FIG. 4 illustrates on a larger scale a plan view of a section of one of the metal discs of this heat exchanger.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Plate heat exchangers of the present type are in general specially designed and made for certain definite through-flow media and the transfer of a certain amount of heat. For instance, the heat exchanger may be designed for steam air heat exchange, milk steam heat exchange (when pasteurizing milk), milk water heat exchange (when cooling the pasteurized milk) and for similar purposes.

The plate heat exchanger in accordance with FIGS. 1 and 2 consists of a generally cylindrical shell jacket 1 with an inlet 2 and outlet 3 for through-flow of afirst medium. The ends of the shell 1 are closed by walls 4, 5 having an inlet 6 and an outlet 7 for through-flow of the second medium. The shell 1 encloses several metal discs 8 arranged in succession in the axial direction, in which discs 8 three rows of through-flow openings 9, l0, and 11 are formed, each row being circular and arranged one radially outside the other. Rings 12, 13, serving to separate the media flows, are arranged between adjacent metal discs 8, and the entire disc unit is kept integral by means of a central set bolt 14. The inner row of openings 9 and the outer row of openings 11 are intended for passage therethrough by the medium entering through the inlet opening 2, and the middle row of openings is intended for passage therethrough by the medium entering from the inlet 6. For this purpose one junction channel 15, 16 is disposed at each heat exchanger end, these junction channels 15, I6 communicating with the inlet 2 and the outlet 3, respectively, and interconnecting the openings 9 and 11. Furthermore, at the heat exchanger ends are disposed two annular channels 17 and 18 in communication with the inlet 6 and the outlet 7, respectively, and interconnecting the openings 10. The annular channels 17, 18 have cross-wise extending channels 19, 20 intercon' necting, respectively, the outer chamber 21 and the inner chamber 22 of the junction channel 15 and the outer chamber 23 and the inner chamber 24 of the junction channel 16.

Preferably the metal discs 8 are somewhat turned relatively one another about the axis of the heat exchanger whereby the openings 9 11 of one disc will not be positioned directly opposite the corresponding openings formed in the next disc. This ensures that the media passing through the heat exchanger are forced to continually change their direction of movement, and may flow in a zig-zag pattern between the discs 8.

In the following is assumed that the heat exchanger is intended to heat air by means of hot water. The hot water is then inserted through the inlet 6 and forced to flow through the openings 10 and leave through the outlet 7. Disc portion 25 is then heated and heat is transferred from this disc portion in the direction indicated by the arrows 26 and 27 to the radially inner disc portion 28 and the radially outer disc portion 29, which latter disc portions 28, 29 efficiently heat the air streaming past them.

The dimensions of the disc portions 25, 28, and 29 and those of the through-flow openings 9, 10, and 11 are chosen in dependence on the media to be treated by the heat exchanger.

The embodiment of the heat exchanger illustrated in FIGS. 3 and 4 is intended to pre-warm fuels or lubricant oils by means of hot water. The construction and mounting of the various details of this heat exchanger are in principle the same as those of FIG. 1. However, the metal discs 30 (FIG. 4) are provided with five circular rows of through-flow openings, openings 31, 32, and 33 of which are intended for passage therethrough by oil, and openings 34 and 35 intended for passage therethrough by hot water. Disc areas 36 intermediate the openings 31 increase as to their width in the direction towards the disc areas 37 in which the openings 34 are formed. The disc areas 38 between the openings 33 increase in width in the direction towards the disc area 39 in which are formed the openings 35. The openings 32 have a rhomboid, elongate configuration whereby the disc areas 40 and 41 between adjacent openings 32 will increase in width in the direction towards the disc areas 37, whereas the disc areas 41 between the openings 32 will increase in width in the direction towards the disc area 39.

Each end wall 42 and 43 of the heat exchanger in accordance with FIG. 3 is provided with two annular junction channels each 44 and 45 or 46 and 47, respectively, which channels are interconnected by their respective cross channel, 48 or 49, and communicate with an inlet 50 or outlet 51, respectively. The junction channels 44, 45, 46, 47 interconnect the throughflow openings 34 and 35 via through-flow channels 52, 53 and 54, 55, respectively, formed in the end walls 42, 43. These end walls are furthermore provided with junction channels 56 and 57, respectively, communieating with one inlet 58 and one outlet 59 each for the second medium, which in the present instance is oil. The junction channels 56, 57 interconnect openings 31, 32, and 33 via through-flow channels 60, 61, 62 and 63, 64, 65, respectively, formed in the end walls 42, 43. The end walls 42, 43 also have so called blank flanges 66 and 67 sealing the openings 68 and 69 through which it is possible to insert tools to tighten the set bolt 70.

In accordance with FIG. 3 the heat exchanger jacket is formed by the radially outermost metal rings 71 positioned between the metal discs 30.

It should be obvious from FIG. 4 that the transfer of heat from the hot water through the openings 34 and 35 to the oil through the openings 31, 32, and 33 will be extremely good, owing among other things to the shape chosen for the disc areas 36, 38, 40, and 41.

The invention is not to be considered limited by the embodiments as illustrated and described above but several modifications are feasible within the scope of the appended claims. A shape different from the one described may be given to the through-flow openings in the metal discs but as apparent from FIG. 2 these openings should be formed through punching followed by bending sidewise the tongue thus punched, thus providing considerable surface enlargement. It is also preferable to form concentrically extending corrugations in the metal disc, as such corrugated patterns will also considerably increase the area of the heat transfer surface of the discs. Finally, the metal discs should be provided with guiding shoulders keeping the mediumseparating rings l2, 13 in their correct positions. These rings are preferably made from metal and provided on their end surfaces with sealing rings made for instance of Teflon or other suitable materials. It is of course possible to replace any row of through-flow openings by two or several such openings, should this be desirable.

What I claim is:

1. A heat exchanger comprising, in combination:

a plurality of parallel and axially aligned flat metal discs, each having an inner annular row of circumferentially spaced openings, an outer annular row of circumferentially spaced openings and at least one intermediate annular row of circumferentially spaced openings; said rows of openings being similarly arranged on each disc whereby adjacent annular rows of openings of each disc are separated by flat annular regions devoid of openings with such flat regions of adjacent discs being mutually opposed;

a set of concentrically arranged sealing rings disposed between and spacing apart each adjacent pair of said discs, said sealing rings of each set being of different diameters to seat upon the mutually opposed flat regions of the respective discs to interrupt communication between adjacent rows of openings thereof;

compression means for securing said discs and intervening sealing rings in a sandwiched stack whereby fluid tight passages of annular cross section are formed through corresponding rows of said openings from one end of the stack to the other; first header means for directing one fluid through an alternate pair of said annular passages and having an inlet conduit at one end of said stack and an outlet conduit at the other end of the stack; and

second header means enclosed by said first header means for directing a second fluid through at least that annular passage intervening between said alternate pair thereof and having an inlet conduit at said other end of the stack passing through said first header means and an outlet conduit at said one end of the stack passing through said first header means whereby said second fluid flows countercurrently with respect to said one fluid with heat exchange therebetween being effected through said flat annular regions of the discs, said second header means comprising first and second annular members, said first annular member defining an annular channel discharging at said other end of the stack into said intervening annular passage and surrounding an inner space from which fluid is discharged from the innermost of said alternate passages and said first header means comprising a first end portion enclosing said first annular member to define therewith an annular outer space from which fluid is discharged from the outer of said alternate passages, said inner and outer spaces being in communication and said first annular member being connected to said inlet conduit of the second header means, said second annular member defining an annular chamber receiving fluid at said one end of the stack discharged from said intervening passage and surrounding a second inner space discharging fluid into said innermost of the alternate passages and said first header means comprising a second end portion enclosing said second annular member to define therewith an annular second outer space discharging fluid into said outer of the alternate passages, said second inner and outer spaces being in communication and said second annular member being connected to said outlet conduit of the second header means.

2. A heat exchanger as in claim 1 wherein said first header means comprises a shell surrounding said stack and extending beyond the opposite ends thereof, and end plates engaging the opposite ends of said shell, said first and second annular members being sealed on one annular face against the respective end plates and, at their other annular faces, communicating with and connecting the spaced openings of said intervening passage, and wherein said inlet and outlet conduits communicate with the interiors of the annular members through the respective end plates.

3. A heat exchanger as in claim 2 wherein the openings of each disc are circumferentially offset with respect to the corresponding openings of an adjacent disc. 

1. A heat exchanger comprising, in combination: a plurality of parallel and axially aligned flat metal discs, each having an inner annular row of circumferentially spaced openings, an outer annular row of circumferentially spaced openings and at least one intermediate annular row of circumferentially spaced openings; said rows of openings being similarly arranged on each disc whereby adjacent annular rows of openings of each disc are separated by flat annular regions devoid of openings with such flat regions of adjacent discs being mutually opposed; a set of concentrically arranged sealing rings disposed between and spacing apart each adjacent pair of said discs, said sealing rings of each set being of different diameters to seat upon the mutually opposed flat regions of the respective discs to interrupt communication between adjacent rows of openings thereof; compression means for securing said discs and intervening sealing rings in a sandwiched stack whereby fluid tight passages of annular cross section are formed through corresponding rows of said openings from one end of the stack to the other; first header means for directing one fluid through an alternate pair of said annular passages and having an inlet conduit at one end of said stack and an outlet conduit at the other end of the stack; and second header means enclosed by said first header means for directing a second fluid through at least that annular passage intervening between said alternate pair thereof and having an inlet conduit at said other end of the stack passing through said first header means and an outlet conduit at said one end of the stack passing through said first header means whereby said second fluid flows countercurrently with respect to said one fluid with heat exchange therebetween being effected through said flat annular regions of the discs, said second header means comprising first aNd second annular members, said first annular member defining an annular channel discharging at said other end of the stack into said intervening annular passage and surrounding an inner space from which fluid is discharged from the innermost of said alternate passages and said first header means comprising a first end portion enclosing said first annular member to define therewith an annular outer space from which fluid is discharged from the outer of said alternate passages, said inner and outer spaces being in communication and said first annular member being connected to said inlet conduit of the second header means, said second annular member defining an annular chamber receiving fluid at said one end of the stack discharged from said intervening passage and surrounding a second inner space discharging fluid into said innermost of the alternate passages and said first header means comprising a second end portion enclosing said second annular member to define therewith an annular second outer space discharging fluid into said outer of the alternate passages, said second inner and outer spaces being in communication and said second annular member being connected to said outlet conduit of the second header means.
 2. A heat exchanger as in claim 1 wherein said first header means comprises a shell surrounding said stack and extending beyond the opposite ends thereof, and end plates engaging the opposite ends of said shell, said first and second annular members being sealed on one annular face against the respective end plates and, at their other annular faces, communicating with and connecting the spaced openings of said intervening passage, and wherein said inlet and outlet conduits communicate with the interiors of the annular members through the respective end plates.
 3. A heat exchanger as in claim 2 wherein the openings of each disc are circumferentially offset with respect to the corresponding openings of an adjacent disc. 